Malicious PDF — malware analysis report

Static analysis result for SHA-256 5bf36cb0abf5c2da…

MALICIOUS

PDF

100.9 KB Created: 2021-01-31 21:56:03 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-17
MD5: 6bec3216689d9d40c8d4001a3612a3ef SHA-1: d99e46a39e4d72985e07b047b6ab2a01a8580aa8 SHA-256: 5bf36cb0abf5c2da00b5fd1b30bcb33e54c41210d452e6b1dbbc987a0520818c
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file contains a large number of external links, a technique often used for SEO manipulation or to distribute malicious payloads. The ML classifier strongly indicates maliciousness, and the presence of numerous links to potentially disposable hosting services further supports this. No scripts were extracted, but the primary attack pattern involves redirecting users to external resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://jacksth.ru/123?utm_term=rsync+link-dest+incremental+backup PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4446045/normal_600ecf43ae628.pdfIn PDF document text
    • https://juwibaviwexufeb.weebly.com/uploads/1/3/0/7/130739975/7f18328a1f3f.pdfIn PDF document text
    • https://nebumokijisuj.weebly.com/uploads/1/3/5/3/135326708/1458816.pdfIn PDF document text
    • https://webebusili.weebly.com/uploads/1/3/0/9/130969565/56d1d3c.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4480161/normal_5fc71bd27fa99.pdfIn PDF document text
    • https://gutugifowofe.weebly.com/uploads/1/3/1/6/131606479/somabi.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4529024/normal_600f74d724bc2.pdfIn PDF document text
    • https://putoluvutawubu.weebly.com/uploads/1/3/1/4/131437806/podoj.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4418167/normal_5ff3f017f2b4f.pdfIn PDF document text
    • https://zaloposigino.weebly.com/uploads/1/3/0/7/130739621/vetanegewoju_dizizojopojagix.pdfIn PDF document text
    • https://sovopedu.weebly.com/uploads/1/3/5/3/135301682/fobimeriz_serimuto_nesapabalabota.pdfIn PDF document text
    • https://cdn.sqhk.co/tudusiki/fkajjqI/88768263611.pdfIn PDF document text
    • https://cdn.sqhk.co/somisafeg/hgjmwie/98452288216.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/vibasujefir/jijedorujejegeridose.pdfIn PDF document text
    • https://s3.amazonaws.com/bitizopovopaso/54848215740.pdfIn PDF document text
    • https://s3.amazonaws.com/genedonapubefe/98961789843.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00014b2e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14B2E 5564 bytes
SHA-256: 8906d0cd4f1118b93cd20adec03905d86723ddc2b13a1b573990d4ed6fff580f
font_01_sfnt_off00015e12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15E12 11840 bytes
SHA-256: 7c1215784f120af3e4f48c6f30ff3be5fdfad6f329b46a6513e2a6c960821aed

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